Dwarf male
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As dwarf male is referred to in the Zoology an adult male of a type that is substantially smaller in comparison to the female specimens. This extreme sexual dimorphism is mainly found in invertebrates as well as in some deep-sea fish .
Because of their small size, dwarf males often use different food resources than the females, so that food competition between the sexes is reduced. In sparsely populated habitats (e.g. deep sea ) the male often lives on or even in the body of the female and is thus available for fertilization when laying eggs without having to search for energy.
Males need a smaller body size to produce sperm than females need to produce nutrient-rich egg cells . Sometimes the male also serves as food for the female after mating if it does not move away quickly enough.
Examples of the appearance of dwarf males:
- some spiders
- many barnacles
- Paper boats (squids)
- some worms , e.g. B. Beard worms of the genus Osedax or hedgehog worms of the Bonelliidae family , best studied in the green hedgehog worm
- Deep-sea fish such as deep-sea frogfish : in some species the degenerating male grows together with the female and is also nourished by the female bloodstream ( parabiosis or parasitism ).
The cichlid Lamprologus callipterus from the East African Lake Tanganyika has both normal-sized males and dwarf males. The smaller morph can invade the nest of the larger competitor unnoticed and inseminate the eggs deposited there .
Individual evidence
- ↑ Spektrum.de Lexicon of Biology: Parasitism II . 1999. Spectrum Academic Publishing House, Heidelberg
- ↑ Spektrum.de Lexicon of Biology: Deep sea angler . 1999. Spectrum Academic Publishing House, Heidelberg
- ↑ Schütz, D., G. Pachler, E. Ripmeester, O. Goffinet and M. Taborsky (2010): Reproductive investment of giants and dwarfs: specialized tactics in a cichlid fish with alternative male morphs . Funct. Ecol. 24 (1): 131-140.
Web links
- Spektrum.de Lexicon of Biology : Miniature males
- to Lamprologus callipterus